Oooo that's a nice character concept! Love myself some fantasy themed art heh.
The sketch I did may be a bad example, but I've replicated the pose you've drawn on the far left and as you can see all the lines are almost parallel or perpendicular. In most cases having parallel lines like this on an organic figure will make them look very stiff and unlively.
For standing poses ( and in most cases all poses ) to look dynamic and lively you will generally want to leave those parallel lines out. I've recreated the pose by using lines that try to zigzag and meet each other and also included a bit of gesture. This can really help make your figures feel grounded and alive.
I'm not very well equipped to give criticism yet, so please take what I say with a grain of salt! Some things I say may be correct, some things may be wrong.
EDIT: Your character is a mannequin so maybe these don't apply, but depending on how willing you are to exaggerate the pose of the mannequin it could help make it look more animated.
